Parametric Modeling And Experimental Study Of Porous Foam Metal Magneto-rheological Fluid Damper

Mechanical vibration is ubiquitous in engineering,and it is significant to reduce the impact of mechanical vibration.Magneto-rheological(MR)fluid dampers are widely used in various fields due to their adjustable damping force,fast response time and low energy consumption.However,with the development of science and technology,conventional MR fluid dampers have been unable to meet the needs of vibration isolation of instrument since those instruments and equipment have become more and more precise and integrated.The MR fluid damper based on porous material,compared with conventional MR fluid damper,has great advantages in the field of vibration isolation of precision instrument because it does not need complicated dynamic sealing and its lower cost and longer service life.Aiming at the current problems of this type of damper,this paper proposes a new type of porous foam metal MR fluid damper which is quadru-pole.This paper mainly carries out the following work:Firstly,aiming at the problems,for example,low effective area ratio and serious magnetic field loss,of the traditional porous metal foamed MR fluid damper,a new damper structure is proposed and the magnetic field simulation of the damper was carried out by JMAG-Designer(an electromagnetic finite element analysis software).The simulation results show that the magnetic induction intensity of the shear gap of this damper can reach 0.52 T at the maximum,and the structure and magnetic circuit design of the damper are reasonable.Secondly,a pseudo-static model of a porous foam metal MR fluid damper is established based on the Bingham constitutive model of MR fluid,then,the model is used to calculate the output force of the damper to provide a reference for performance testing.A damper dynamic performance test system is built.The test results show that the damper has excellent semi-active performance and the output force of the damper increases as the current increases,besides,the damping force peak and the adjustable multiple which can reach 29 are much larger than the conventional porous foam metal MR fluid damper.Then,using the Simulink(a visual simulation software)to build a classic Bouc-Wen model,the test data and NLLS-TRA algorithm are used to identify the model parameters.Obtained a parametric dynamic model of a porous foam metal MR fluid damper by bringing the parameter value back.Using the prediction results to verify the fitting results.The simulation results of the model in both cases are in good agreement with the experimental data,indicating that the model can simulate the dynamic performance of the porous foam metal MR fluid damper.Finally,a vibration isolation platform with damper and compression spring in parallel is built,then,the trend of acceleration transfer with current at different frequencies is obtained through testing it with vibration isolation performance test system.When the frequency ratio is greater than,it has excellent vibration isolation performance,and the acceleration transfer rate increases as the current increases.When the frequency ratio is less than,although it cannot play the role of vibration isolation,the acceleration transmission rate of the vibration isolation platform decreases as the current increases,which can effectively reduce the impact of vibration on the equipment.The experimental results show that the vibration isolation device composed of the damper designed in this paper has excellent vibration isolation performance.